Apparatus for mounting a tone generator and for positioning the same relative to a transducer



May 21, 1968 H. B. RHODES 3, 8 ,699 APPARATUS FOR MOUNTING A TONE GENERATOR AND FOR POSITIONING THE SAME RELATIVE TO A TRANSDUCER Filed Dec. 16, 1964 4 Sheets-Sheet l f E I INVENTOR. #42040 5 @4005) Filed Dec. l6, 1964 H. B. RHODES APPARATUS FOR MOUNTING A TONE GENERATOR AND FOR POSITIONING THE SAME RELATIVE TO A TRANSDUCER ..m!mmmnumw- 4 Sheets-Sheet 2 Iii INVENTOR. 1 /4/8040 5. 2 /0953 H. B. RHODES May 21, 1968 APPARATUS FOR MOUNTING A TONE GENERATOR AND FOR POSITIONING THE SAME RELATIVE TO A TRANSDUCER Filed Dec. 16, 1964 4 Sheets-Sheet 3 INVENTOR. ,ewazofifilwoz's y 21, 1968 H. B. RHODES 3,384,699

FOR MOUNTING A TONE APPARA GENERATOR AND FOR POSIT NG THE SAME RELATIVE TO A TRANSDUC Filed Dec. 16, 1964 4 S tS-Sheet 4 United States Patent 3,384,699 APPARATUS FOR MOUNTING A TONE GENERA- TOR AND FOR POSITIONING THE SAME RELA- TIVE TO A TRANSDUCER Harold B. Rhodes, Anaheim, Calif., assignor, by mesne assignments, to Columbia Broadcasting System, Inc., New York, N.Y., a corporation of New York Continuation-impart of application Ser. No. 241,270, Nov. 30, 1962. This application Dec. 16, 1964, Ser. No. 421,148

39 Claims. (Cl. 84-1.14)

This application is a continuation-in-part of my copending patent application Ser. No. 241,270, filed Nov. 30, 1962, now abandoned, for an Apparatus for Mounting a Tone Generator, and for Positioning the Same Relative to a Transducer.

This invention relates to an apparatus for mounting and adjusting the tone generators in an electrical musical instrument of the iano type. Such a musical instrument is described in my Patent No. 2,972,922, issued Feb. 28, 1961, for an Electrical Musical Instrument in the Nature of a Piano, and in my co-pending patent application Ser. No. 225,917, filed Sept. 24, 1962, for a Piano Action.

An object of the present invention is to provide a highly simple, economical and effective apparatus for mounting and adjusting tone generators relative to their associated pickups or transducers, the apparatus being characterized by extreme simplicity and accuracy of adjustment.

Another object is to provide an apparatus for mounting tone generators in such manner that they will withstand extensive jolting, shaking and vibration during shipment and use.

A further object is to provide a tuning fork-mounting means which acoustically isolates the fork from a fixed support, which permits the position of the fork to be readily and accurately adjusted, and which is sufficiently rugged to withstand the strains which occur during shipment.

A further object is to provide a piano-type electrical musical instrument'wherein the timbre, volume, etc., of the generated note may be adjusted through use of one hand of the operator while the other hand is employed to strike the piano key.

A further object is to provide a tone-generator mounting and adjustment means which does not interfere with vibration of the generator, so that the maximum response is achieved upon striking of the associated piano key.

A further object is to provide a mounting means which serves also as an electrical shield.

These and other objects and advantages of the invention will be more fully set forth in the following specification and claims, considered in connection with the attached drawings to which they relate.

In the drawings:

FIGURE 1 is a sectional view taken vertically through one embodiment of a piano-type electrical musical instrument, incorporating the present invention, and illustrating a tone-generator apparatus and the associated piano action, transducer, amplifier and loudspeaker, etc.;

FIGURE 2 is an enlarged fragmentary vertical sectional view illustrating the apparatus for mounting and adjusting the tone generator shown in FIGURE 1;

FIGURE 3 is a view corresponding generally to FIG- URE 2 but illustrating, in dashed and solid lines, various adjusted positions of the tone generator;

FIGURES 4, 5, 6 and 7 are transverse sectional views taken, respectively, on lines 4-4, 5-5, 6-6 and 7--7 of FIGURE 2;

FIGURE 8 is a fragmentary plan view of the instrument, illustrating three white keys and two black keys;

FIGURE 9 is a sectional view corresponding generally 3,384,699 Patented May 21, 1968 "Ice to FIGURE 2 but showing a second embodiment of the invention;

FIGURE 10 is a transverse section on line 10-10 of FIGURE 9;

FIGURE 11 is a fragmentary plan view, showing an adjustment means as seen from station 11-11 in FIG- URE 9;

FIGURE 12 is a vertical sectional view illustrating a third embodiment;

FIGURE 13 is a transverse section on line 13-13 of FIGURE 12;

FIGURE 14 is a vertical sectional view illustrating a fourth embodiment; and

FIGURE 15 is a transverse section on line 1515 of FIGURE 14.

The mounting and adjustment apparatus shown in FIG- URES 1-11 is particularly adapted for tone generators adapted to produce tones of relatively low or intermediate pitch, for example all notes below high C (the C one octave above middle C). It is to be understood, however, that such mounting and adjustment apparatus may also be employed for a number of higher-pitched tones.

Referring first to the embodiment of FIGURES 1-8, the apparatus may be seen to comprise a plurality of horizontal support elements 10, 11 and 12 which may be suitably mounted above a horizontal bottom element 13, for example by means of upwardly-extending end elements one of which is shown at 14. The various elements 10-44 support all of the components of the electrical musical instrument, but (except relative to the fragmentary plan view of FIGURE 8) only one such component will be described herein. It is to be understood that the remaining components of the instruments, adapted to generate notes of different low or intermediate pitches, are constructed substantially the same as will be described in detail below relative to the illustrated mechanism.

Mounted on the horizontal bottom element 13 is a piano key 16 having an outer portion 17 adapted to be struck by the pianist. The key also has an inner portion 18 adapted to actuate a hammer element 19 which is pivoted at 21 to the support element 12. As described in detail in the above-cited co-pending patent application Ser. No. 225,917, striking of the outer key portion 17 effects upward pivotal movement of hammer element 19 in a vertical plane until the hammer head 22 engages the tine or reed 23 of the associated tone generator 24. Furthermore, and also as described in such co-pending patent application, upward pivotal movement of the hamrner effects downward movement of an associated damper means 26 until (as shown in FIGURE 2) it no longer contacts the tine or reed 23.

In view of the fact that the piano action is described in great detail in co-pending patent application, Ser. No. 225,917, and also in view of the fact that the present invention is usable with various types of piano actions and also other means for striking the tone generator, it is believed that further description of the piano action is unnecessary.

As described in detail in the above-cited patent, the tine or reed 23 constitutes one leg of a type of tuning fork in which the remaining leg 27 has a very much greater mass, the highand low-mass legs 27 and 23 being tuned (resonant) to each other. Stated more specifically, the low-mass leg or tine 23 may be a piece of piano wire one end of which is rigidly mounted in a lug 28 which depends from and is integral (or rigidly connected) with the highmass leg 27. The high-mass leg 27, which may comprise an iron casting, has in some instances an enlarged Weight portion 29 remote from lug 28. Such leg is generally parallel to the low-mass leg or tine 23.

A mounting portion, base or prong 31 is provided on the tone generator on the opposite side of lug 28 from the legs 23 and 27. Such base or prong is preferably in alignment and integral with the high-mass leg 27, being sufliciently long to permit it to be incorporated in lever means to be described hereinafter.

In accordance with one important feature of the present invention, lever means are provided to cantilever the entire tone generator or tuning fork 24 from its base or mounting portion 31, such lever means being adjustable in order to vary the position of the tine 23 relative to a transducer or pickup which is shown at 32. The illustrated lever means is preferably used as a third-class lever having a fulcrum at 33, adjacent the extreme free end of base 31, and also having a force-applying portion 34 which is adjustable to pivot the generator 24 upwardly and downwardly between various positions such as are shown in solid and dashed lines in FIGURE 3. The position of the free end of tine 23 is thus accurately adjusted relative to the pickup 32.

Stated in greater detail, the apparatus for mounting and adjusting the tone generator or tuning fork 24 comprises an elongated channel bar 36 disposed in inverted relationship and bridged between two horizontal supports 10 and 11. Screws 37 and 38 are extended downwardly through horizontal slots 39 in the web of channel 36, such screws extending into the supports 10 and 11 and being adapted to be loosened in order to permit adjustment of the channel in an axial direction. Such axial adjustment of the channel changes the distance between the end of tine 23 and the pickup 32, thereby regulating factors such as tone character and volume.

The flanges 41 of channel 36 are, as shown best in FIG- URES 4 and 5, spaced apart sufficiently far to receive the base 31 and high-mass leg 27 in loose-fitting relationship. Thus, the flanges do not interfere substantially with vibration of the tuning fork, but they do provide a limiting function preventing excessive lateral movement thereof.

It is to be understood that the channels for all of the tone-generators are disposed adjacent each other, as shown in FIGURE 8, this being practical because the flanges provide a spacing effect preventing one high-mass leg 27 from contacting the corresponding leg 27 of the tone generator on either side thereof.

A strip of felt 42 may be mounted loosely over each tone generator, adjacent the base portion of high-mass leg 27. Such felt prevents direct contact between leg 27 and the flanges 41.

In order to insure that the tone generator 24 remains in the lowest possible position permitted by the fulcrum 33 and by the seting of force-applying means 34, a helical compression spring 43 is provided. Such spring is seated in a suitable bore 44 formed in the tone generator in alignment with lug 28, the felt 42 having an opening or slot registered with the bore 44. The bias of the spring augments the weight of high-mass leg 27 (including its end portion 29) in insuring that the free end of base 31 remains in engagement with fulcrum 33. The spring bias holds the tone generator in position during striking by hammer 22, and also prevents undesired movements and rattling during shipment of the instrument.

The fulcrum portion 33 of the lever means is illustrated to comprise a cap screw which is threaded downwardly through an internally-threaded opening in the web of channel 36. A spring 46 is seated between the head of the screw and the upper surface of channel 36, in order to prevent rotation of the screw except during adjustment thereof. It is to be understood that adjustment of the screw provides some regulation of the distance between the tone generator 24 and the piano action, such adjustment being normally effected at the factory. Instead of providing an adjustable fulcrum means 33, a dimple may be provided in downwardly-extending relationship in the web of the channel 36, this being considerably more economical than the adjustable screw.

The force-applying portion 34 of the lever means is illustrated to comprise another cap screw which extends downwardly through an oversize opening 47 in the channel web. The screw is threaded through an internallythreaded bore in the base 31 of the tone generator or tuning fork, such bore being intermediate the fulcrum portion 33 and the lug 28.

The screw element or force-applying portion 34 is adapted to be turned by the operator, either at the factory or subsequently, in order to adjust accurately the position of the free end of tine or reed 23. Thus, for example, turning of the screw 34 in such a direction as to cause the tuning fork base 31 to move upwardly causes upward pivotal movement of the tone generator 24 from the dashedline position shown in FIGURE 3 to the solid-line position shown therein, or to any intermediate position.

The illustrated mechanical-electrical transducer or pickup 32 comprises a permanent-magnet core 48 which is mounted in a horizontal position, in general alignment with the tine or reed 23, by means of a suitable bracket 49. A coil 51 (FIGURE 1) is wound around the core 48 and is connected through leads 52 to an amplifier 53, the latter being in turn connected to a loudspeaker 54. The end of core 48 (adjacent the tine) is tapered to a chisel edge 56 which is disposed horizontally, as shown in FIG- URE 6.

In adjusting the apparatus shown in FIGURES 1-8, the operator may loosen the screws 37 and 38 and effect longitudinal shifting of channel 36 until the free end of tine 23 is the desired distance from chisel edge 56. Such adjustment may be effected with one hand, while the other hand is employed to strike the associated piano key 16. When the gap between chisel edge 56 and the free end of tine 23 is relatively wide, the tone is soft and mellow since? the magnetic field generated by transducer core 48 is relatively weak. When the free tine end is close to chisel edge 56, the tone is relatively sharp and loud.

Turning of the screw or force-applying means 34 effects the above-indicated pivotal movement of the entire tone generator 24 to adjust the elevation of the free tine end relative to the chisel edge 56. Such adjustment affects greatly the timbre or harmonic content of the note which is produced in the loudspeaker 54 in response to striking of the piano key 16. Since the indicated adjustment is extremely important and critical, the making thereof with simplicity, utilizing only one hand of the operator so that the other may be employed to repeatedly strike the piano key, is an important advantage achieved by the present construction.

After the instrument is properly adjusted as described above, it may be played by striking the outer portion 17 of piano key 16 to effect upward pivotal movement of the hammer head 22 from the rest position shown in FIGURE 1 to the actuated position shown fragmentarily in FIGURE 2. The tine or reed 23 is thus caused to vibrate in a vertical plane, such vibration being sensed by the transducer or pickup 32 which generates a corresponding electrical current for transmission through amplifier 53 to loudspeaker 54.

The described apparatus for mounting and positioning the tone generator 24 is simple, economical, rugged and effective. Furthermore, it affords the distinct advantage that tampering with the piano action, pickup 32, etc., by an inexperienced operator is prevented due to the arrangement of the large number of closely adjacent channels 36. Thus, the only things which the operator sees upon removing the cover or casing (not shown) for the present instrument are the channels 36, which may be appropriately colored or decorated if desired. Such channels are so close together that the operator may not reach or even see the piano actions therebeneath.

A further important advantage is that the channels 36 provide an effective electrical shield for the transducers 32 and associated leads. Thus, the system is protected from extraneous electrical signals such as are generated by fluorescent lights, for example. Desirably, the channels are formed of steel or aluminum.

It is to be understood that various modifications of the present principle may be made in order to save costs, although achieving less than the entire benefit of the present invention. For example, the channel 36, or equivalent guiding and supporting element, may be cantilevered entirely from the support 10, and cut off at a point adjacent the region where base 31 merges into lug 28. This eliminates the need for the felt 42, and reduces somewhat the weight of the instrument. In such an arrangement, both of the screws 37 and 38 may be inserted through slots (corresponding to 39) which are provided in the channel portion above support 10, both screws being inserted into such support 10.

EMBODIMENT OF FIGURES 9-11 Except as will be specifically described, the embodiment of FIGURES 9-11 is identical to that of FIGURES 1-8. Elements in FIGURES 9-11 which correspond to those in FIGURES 1-8 have been given the same reference numerals, except followed in each instance by the letter a.

In the embodiment of FIGURES 1-8, the channels 36 are mounted on the supports 10 and 11 in relatively fixed relationship. In the embodiment of FIGURES 9-11, the channels 36a are mounted to supports 10a and 11a in flexible, acoustically-isolated relationship, thereby more effectively isolating the tone generators 24a from the supports 10a and 11a. It is an important feature of the embcdiment of FIGURES 9-11 that such acoustic isolation is achieved between the channels 36a and the supports 10a-11a while still permitting longitudinal shifting of the channels 36a in order to vary the distance between pickups 32a and the ends of tines 23a.

To achieve the above-indicated result of substantially acoustically isolating each channel 36a from the supports 10a and 11a, and permitting limited pivoting of the channels relative to the supports, the ends of the channel flanges 41a are removed so that channel web portions 60 and 61 extend from opposite ends of the channel 36a. Referring first to the channel end which is relatively adjacent the lever means, the channel web extension 60 rests on a strip 62 of felt or other soft material adapted to permit vibration of the channel, and to permit a limited degree of pivoting thereof relative to the support 10a (about a longitudinal axis), as desired. A slot 63 is formed in the channel extension 60 in order to receive a mounting screw 64 which extends downwardly through the felt strip 62 into the support 100. A washer 66, formed of felt or equivalent soft material, is inserted between the head of the screw and the upper surface of web extension 60. The screw head is not tightly clamped against the felt washer, the relationship instead being sufficiently loose to permit the above-indicated channel vibration and pivoting, and also to permit longitudinal shifting of the channel within the limits imposed by the ends of slot 63.

Proceeding next to a description of the mounting for the other end of each channel, the remaining channel web extension 61 is also seated on a felt strip 67, being longitudinally slotted at 68 to receive a downwardlyextending mounting screw 69. The screw 69 also extends through a small hole in one end of a thin flat spring 71 having sufficient resilience to permit the above-indicated vibration and pivoting of the channel 36a. However, spring 71 has sufficient rigidity in a longitudinal direction to prevent longitudinal shifting of the channel 36a except in response to loosening of an additional screw 72.

The spring 71 is also sufiiciently rigid to insure that the channel 36a will not move upwardly off the felt strip 67, unless the hammer blow is very hard. In the latter event, the spring 71 aids in absorbing the shock of the hard blow.

The screw 72 extends downwardly through a longitudinal slot 73 in the spring end which is remote from screw 69, being threaded into an internally-threaded web portion 74 of channel 36a. A lock washer 76 is provided between the spring end and the channel portion 74 in order to prevent relative longitudinal movement between the channel and the spring except during adjustment periods, when the screw 72 is intentionally loosened.

Referring next to FIGURE 10, it is pointed out that the flange sides 41a may be, in the present embodiment, bent or pinched against the adjacent regions of the felt 42a in order to relatively firmly grip element 27a and thereby insure against contact between such element and the channel flanges 41a. Such gripping is not tight, being instead sufiiciently loose to permit the above-indicated adjustment of the tone generator 240 in the channel and in response to operation of one or both of the screws 33a and 34a.

It is to be understood that the felt strip 32a may be eliminated, for example when it is desired to use elements 27a having greater thickness. This is because it has been found that, despite the absence of the felt 42a, the tone generators 24a normally remain spaced from the channel flanges 41a so that vibration or the tone generator is not adversely affected.

In the operation of the embodiment of FIGURES 9-11, the pivoted position of the tone generator 24a is adjusted as described heretofore, by adjusting one or both of the screws 33a and 34a. Striking of the tine or reed 23a by hammer 22a then sets the tone generator 24a into vibration, such vibration being relatively independent of the channel 36a. However, such vibration as is transmitted to channel 36a is not transmitted from such channel to the supports 10a and 11a, because of the acoustic-isolating mountings 62, 66, 67, 71, etc., described above. Thus, the tone generator 24a is effectively isolated from the fixed supports 10a and 11a, so that there is no interaction between the various tone generators.

In order to further insure against interaction between the various tone generators, sufficient clearance is provided between the adjacent channels 36a to permit a slight amount of pivotal movement thereof about the longitudinal channel axes, without substantially touching. Such pivotal movement, which is made possible by the present mounting means for the channels, insures that each tine 23a will always vibrate in a vertical plane only, as described in the cited patent.

To effect longitudinal adjustment of tone generator 27a relative to the pickup 32a, it is merely necessary for the operator to loosen the screw 72 and then shift the entire channel to the desired longitudinal position. Such shifting is permitted because of the presence of slot 73, and also slots 63 and 68, and because of the relatively loose relationship which mounting screw 64 has at all times relative to the channel extension therebeneath. After the desired position is achieved, screw 72 is tightened so that the spring 71 prevents longitudinal shifting of the channel despite the presence of slots 63 and 68 in the ends of the channel web portion.

Spring 71 cooperates effectively, as described heretofore, with the mounting elements 62-67 and associated parts to etfect acoustic isolation of the channel 36a from the supports 10;: and 11a and to permit vibration and pivoting of the chanel (about the longitudinal axis thereof) as is desirable in order to prevent interaction between the various tone generators and in order to prevent the tine 36a from vibrating in a plane other than a vertical plane.

EMBODIMENT OF FIGURES 12-13 FIGURES 12 and 13 illustrate an embodiment which is particularly adapted to be employed with tone generators which generate the higher-pitched notes, for example those above high C. Such tone generators are described in detail in the above-cited patent.

Except as will be specifically stated, the embodiment of FIGURES 12-13 is identical to that of FIGURES 911. Elements in FIGURES 12-13 which correspond to those in FIGURES 9-11 have been given the same reference numerals, except followed in each instance by the letter b.

The cantilevered mounting relationship is achieved by providing a relatively soft fulcrum pad 80, preferably formed of felt, between the web of channel 36b and the end portion of the base or prong 31b. A cap screw 81 is inserted downwardly through an oversize opening 82 in the channel web, being threaded into base 3112 as in the case of screw 34a of the previous embodiment. Such base 31b (and base 31a in FIGURE 9) is preferably counterbored adjacent the lower end of the screw. Opening 82 is sufliciently large to permit pivotal movement of the tone generator 24b, but sufliciently small to prevent substantial longitudinal movement thereof relative to channel 361).

An additional pad, indicated at 83 in FIGURES 12 and 13, is mounted adjacent the end of the tone generator portion 2711 which is remote from base 31b. Such additional pad is also preferably formed of felt, and seats between the web of the channel and the upper surface of element 271;. Pad 83 prevents excessive upward shifting of the tone generator during a hammer blow, and

during shipment.

It is emphasized that the screw 81 should not be excessively tightened, so that the pads 80 and 83 are compressed substantially. Instead, the action is one in which pad 80 is compressed substantially entirely as a result of the weight of the portions 27b and 28b of the tone generator, whereas pad 83 is compressed hardly at all.

As in previous embodiments, adjustment of the element 81 elfects a pivotal action relative to the fulcrum pad 80, so that the end of the tine or reed 23b is adjusted vertically relative to pickup 3212.

Although the screw 81 is relatively loose, it has been found that the end of the tone generator remote from lever means 80-81 does not remain in contact with either of the channel flanges 4112. Instead, such tone generator bar 27b tends to remain, as desired, in a spaced position between the flanges. This only occurs, however, if the screw 81 is not tightened excessively. If such screw is excessively tightened, and if the tone generator is jolted to a position at which the distal end thereof is engaged with a flange 41b, the locking relationship effected by the pad 83 (when the screw 81 is excessively tightened) may cause the tone generator to remain in contact with a flange. Such action is not desired in that the characteristics of the generated note are then adversely affected.

EMBODIMENT OF FIGURES 14-15 In the embodiment of FIGURES 14-15, each tone generator 240 (for example, comprising any type described in the cited patent, for generating both highpitched notes and low-pitched notes) is cantilevered entirely from one support element such as the one indicated at c.

Except as will be specifically described, the construction of the embodiment of FIGURES 14-15 is the same as that of the embodiment of FIGURES 1-8. Elements in FIGURES 14-15 which correspond to those in FIG- URES 1-8 have been given the same reference numerals, except followed in each instance by the letter 0.

In the present embodiment, the channels may be eliminated and replaced by lever means for associating the tone generator base or prong 31c directly with the mounting support 10c. Such means comprises a pair of parallel screws 90 which extend downwardly through spaced, oversize bores 91 in base 31c, being threaded into the upper portion of support 100 which is preferably formed of wood. Suitable spring means are provided to bias the base 310 upwardly whereby to maintain the upper surface of such base 310 in bearing relationship with soft washers 94 (preferably formed of felt) which seat between the screw heads and the upper prong surface. Such spring means are illustrated to comprise helical compression springs 92 which are seated between the upper surface of support 100 and the bottoms of counterbores 96, the latter being provided in the lower portion of prong 31c coaxially of bores 91. Thus, the screws extend through the springs 92 and downwardly into the Wooden support.

The tone generator 24c is maintained in cantilevered, floating relationship by the springs 92. Thus, striking of the tine or reed 23c by the hammer 22c causes the tone generator to vibrate independently of the support 10c. The tone generator may be pivoted, or shifted upwardly and downwardly without pivoting, by adjusting either or both of the screws 99. In this manner, the position of the tine 230 relative to the piano action, and relative to the pickup 32c, may be adjusted.

In order to shift the tone generator 24c longitudinally relative to the pickup 32c, or relative to another pickup of the electromagnetic or capacitive type, the support means may be adjusted, as may individual sections thereof (one section for each tone generator or each group of adjacent tone generators). Furthermore, means may be provided to shift the pickup 32c longitudinally relative to the tone generator. Such an adjustment means is indicated schematically at 97, being mounted, for example, on the remaining support 110. The adjustment means 97 incorporates set screw or other means for loosening the support for pickup 32c, so that such pickup may be adjusted longitudinally to any desired position prior to re-locking or setting of the set screw. In addition, the adjustment means 97 may incorporate means to permit the pickup 32c to be adjusted in other directions.

It is emphasized that the position of the tone generator 240 is related not only to the position of the pickup 320 but also to the position of the action described in the cited patent application Ser. No. 225,917. Thus, even in constructions wherein the position of the pickup 320 is adjusted independently, it is important that the position of the tone generator 240 be adjustable in order to determine the exact point where the hammer 220 will strike the time 23c, to determine the escapement distance between hammer and tine when the piano key is maintained depressed, and other factors.

The heads of screws 90 are shown as having frustoconical lower surfaces, which surfaces are located above corresponding frusto-conical counterbores in the upper surface of base 31c (coaxially around the respective bores 91). Such conical surfaces and counterbores perform a beneficial self-centering function which minimizes contact between the screws and the walls of bores 91.

It is to be understood that the spring 92 most remote from the leg elements 230 and 27c may compress when tine 230 is struck a hard hammer blow. This permits pivoting of the tone generator, and aids in absorbing the shock of such hammer blow.

Relative to the embodiments of FIGURES 1-13, it is pointed out that each pickup may be adjustably suspended from an associated channed bar 36, etc.

It is possible (although less satisfactory) in some cases to insert at least one of the mounting screws through the high-mass leg of the tuning fork instead of through the base or prong thereof. However, such screw should be located in the base region of the fork, in the vicinity of the base, adjacent the base, etc. Such expressions denote that the screw is disposed sufficiently close to the base or prong to prevent excessive damping of the vibration of the high-mass leg. It is possible, at least relative to the tone generators for the lower-frequency notes, to greatly reduce the length of base 31, 31a, etc. In some cases the base 31, etc., may be omitted entirely, in which case the base region becomes the region where the two legs are interconnected.

Various embodiments of the present invention, in addition to what has been illustrated and described in detail, may be employed without departing from the scope of the accompanying claims.

I claim:

1. A piano, which comprises:

an elongated vibratory tone generator having first and second legs and also having a base region in the vicinity of the connection between said legs,

a support,

spring means seated between said support and said base region to maintain said base region spaced from said support,

said spring means being sufficiently strong to support the weight of said tone generator but sufficiently weak to permit sustained vibration of said tone generator,

limit means disposed on the opposite side of said base region from said spring means to limit the movement of said base region in response to the biase of said spring means,

a portion of said limit means engaging said base region being sufficiently soft to permit sustained vibration of said tone generator, and

a piano action including a hammer disposed to strike one leg of said tone generator and set the same into vibration.

2. The invention as claimed in claim 1, in which said portion of said limit means is formed of felt.

3. An electrical musical instrument, comprising:

a tuning fork having a base and a plurality of prongs,

a support,

lever means to mount said base to said support,

said lever means being adjustable to vary the precise position of said base and thus of said prongs,

said lever means being a third'class lever incorporating said base as a component thereof,

mechanical-electrical transducer means,

means to mount said transducer means operably adjacent at least one of said prongs to sense the vibrations thereof, the response generated in said transducer means being determined largely by the adjusted position of said lever means, and

means to excite at least said one prong to set the same into vibration.

4. The invention as claimed in claim 3, in which said lever means includes fulcrum means to pivotally associate said base with said support, and force-applying means operably associated with said base and with said support to pivot said tuning fork about said fulcrum means.

5. The invention as claimed in claim 4, in which bias means are provided to urge said tuning fork to the most extreme position permitted by said force-applying means.

6. An electrical musical instrument in the nature of a piano, comprising:

support means,

a plurality of channel bars mounted on said support means in generally horizontal and parallel relationship,

a plurality of tuning forks each having a base and a plurality of prongs,

means to mount at least part of each of said tuning forks between flange portions of an associated channel,

means to mount each of said transducers operably adjacent at least one of the prongs of an associated tuning fork, and

means to excite said tuning forks to set the same into vibration.

7. The invention as claimed in claim 6, in which each of said first-mentioned mounting means effects mounting of the associated tuning fork in cantilevered relationship from the channel bar therefor, each such mounting means being operably associated with said base of the associated tuning fork.

8. The invention as claimed in claim 6, in which each of said first-mentioned mounting means comprises the force-applying and fulcrum portions of a lever, each such mounting means being operably associated only with said base of the associated tuning fork, each such mounting means being adjustable to shift the position of the tuning fork relative to the associated channel.

9. The invention as claimed in claim 6, in which means are provided to adjust the position of each of said channel bars relative to said support means, thereby permitting further adjustment of the positions of said tuning forks relative to the associated transducers and the as sociated exciting means.

10. The invention as claimed in claim 9, in which said last-named means includes means to acoustically isolate each channel bar from said support means and to permit vibration of each such channel bar about an axis longitudinal thereof.

11. The invention as claimed in claim 10, in which said acoustic-isolation means includes a flat spring extending longitudinally of each channel bar.

12. The invention as claimed in claim 8, in which said fulcrum portion of each lever comprises a soft pad.

13. An electrical musical instrument of the piano type, comprising:

first and second support means spaced horizontally from each other,

an elongated channel bar bridged between said support means and disposed in inverted relationship,

mounting means to secure each end of said channel bar to its associated support means,

said mounting means being adapted to permit adjustment movement of said channel bar in a longitudinal direction,

a tuning fork having a base and a plurality of legs,

said base and at least one of said legs being disposed between the fianges of said channel bar, fulcrum means provided on said channel bar to engage the upper side of said base at the free end thereof,

a force-apply screw extended downwardly through an oversize opening in the web of said channel bar and threaded through an opening in said base,

said screw being between said fulcrum means and said legs,

mechanical-electrical transducer means fixedly mounted adjacent the end of the other of said legs, and

a piano action including a hammer positioned to strike said other leg and set the same into vibration in a vertical plane.

14. The invention as claimed in claim 13, in which said mounting means for each channel bar end comprises means to acoustically isolate such end from said support means, and in which said channel bar is spaced sufficiently far from other elements of the musical instrument to permit vibration thereof.

15. The invention as claimed in claim 13, in which said transducer means comprises a permanent-magnet core having a horizontal chisel edge adjacent said other leg, and a winding provided around said core, and in which an amplifier and loudspeaker are connected to said winding.

16. The invention as claimed in claim 13, in which compression spring means is seated between said channel bar and said tuning fork at the general region where said base merges with said legs.

17. An electrical musical instrument, comprising:

support means,

an elongated vibratory tone generator,

lever means operably associated with only one end of said tone generator to cantilever the same from said support means,

said lever means being adjustable to vary the position of at least the free end of said tone generator, and

transducer means mounted adjacent said free end of said tone generator.

18. An electrical musical instrument, comprising:

a support,

a plurality of elongated vibratory tone generators, means to mount each tone generator to said support in such manner that a major portion of said tone generator is supported in cantilevered relationship,

said mounting means for each tone generator including fulcrum means to associate said tone generator with said support, said mounting means further including forceapplying operably associated with said tone generator and with said support to compensate for the weight of the cantilevered portion of said tone generator, mechanical-electrical transducer means operably associated with each of said tone generators to sense the vibration thereof, and manually-operated means to set each of said tone generators into vibration. 19. An electrical musical instrument, comprising: a support, a plurality of elongated vibratory tone generators,

each of said tone generators have a base at one end portion thereof,

said base having at least one Opening therethrough, means to mount each tone generator to said support in such manner that a major portion of said tone generator is supported in cantilevered relationship,

said mounting means for each tone generator including fulcrum means .to associate said tone generator with said support, said mounting means further including forceapplying means connected with said support and extended through said opening in said base to support said base and thus compensate for the weight of the cantilevered portion of said tone generator, mechanical-electrical transducer means operably associated with each of said tone generators to sense the vibration thereof, and manually-operated means to set each of said tone generators into vibration. 20. The invention as claimed in claim 19, in which said force-applying means is a screw adjustably connected with said support.

21. An electrical musical instrument, which comprises: a support, a plurality of elongated vibratory tone generators,

each of said tone generators having a base at one end portion thereof,

said tone generator having a plurality of openings therethrough and generally parallel to each other,

said openings being at least adjacent said base, means to mount said base of each tone generator to said support in such manner that a major portion of said tone generator is supported in cantilevered relatio-nship,

said mounting means for each tone generator including a plurality of mounting elements extended, respectively, through said openings and serving to associate said tone generator with said support, mechanical-electrical transducer means operably associated with each of said tone generators to sense the vibration thereof, and manually-operated means to set each of said tone generators into vibration.

22. The invention as claimed in claim 21, in which said mounting elements comprise only two screws.

23. The invention as claimed in claim 21, in which said support is a channel element adapted to receive between the flange portions thereof at least a portion of an associated tone generator.

24. The invention as claimed in claim 21, in which spring means are seated between said tone generator and said support.

25. An electric piano, which comprises:

support means,

an elongated support element,

mounting means to mount one end of said elongated support element to said support means in substantially acoustically-isolated relationship,

said mounting means comprising a soft vibrationdamping element disposed between said one end of said support element and said support means, said mounting means further comprising a fastener inserted through a slot formed longitudinally of said one end of said support element and extending into said support means, second mounting means to mount the other end of said support element to said support means in substantially acousticallydsolated relationship,

said second mounting means including a soft vibration-damping element disposed between said support means and said other end of said support elements, said second mounting means further comprising a second fastener extended through a longitudinal slot in said other end of said support element whereby to cooperate with said first-mentioned fastener and slot to permit longitudinal shifting of said support element relative to said support means, said second mounting means further comprising an elongated flat spring disposed parallel to said other end of said support element,

said spring having an opening in one end portion thereof and receiving said second fastener in relatively close-fitting relationship, said spring having a slot in the end thereof remote from said fastener and receiving a third fastener which is connected to said support element, whereby loosening of said third fastener permits longitudinal shifting of said support element relative to said support means,

a tone generator mounted on said support element,

a transducer operatively associated with said tone generator, and

manually-operated means to excite said tone generator.

26. The invention as claimed in claim 25, in which said means to mount said one end of said support element to said support means further includes a soft vibrationdamping element disposed between said first-mentioned fastener and said one end of said support element, and in which said first-mentioned fastener is loosely mounted whereby to permit said one end of said support element to vibrate freely.

27. The invention as claimed in claim 25, in which each support element is a channel having depending flange portions provided between said ends of said support element, and in which said ends of said support element comprise only the ends of the web of said channel.

28. The invention as claimed in claim 25, in which each of said tone generators comprises a tuning fork having a base portion, and in which the means to mount said tuning fork to said support element includes a first screw extending loosely through said support element and threaded into said base portion of said tuning fork, and a second screw threaded through said support element and bearing against the base portion of said tuning fork in spaced relationship from said first screw.

:29. The invention as claimed in claim '25, in which each of said tone generators comprises a tuning fork having a base portion, and in which the means to mount said tuning fork to said support element comprises a 13 first screw extending loosely through saidsupport ele-' ment and threaded into the base portion of said tuning fork, and a soft pad provided between the base of said tuning fork and said support element at a region relatively adjacent said scre'w, said pad being disposed on the opposite side of said screw from the legs of said tuning fork.

60. An electrical musical instrument, comprising: a tuning fork having a base and a plurality of legs, manually-operable hammer means to strike one leg of said tuning fork and set the same into vibration in a predetermined plane,

pickup means operatively associated with said fork to sense the vibration thereof,

a support element for said tuning fork, and first and second screws disposed generally in said plane of vibration and in generally perpendicular relationship relative to said one leg,

said screws being adapted to support said tuning fork from said support element in cantilevered relationship,

said first screw being threaded downwardly through said support element and bearing against said base at the end portion thereof remote from said legs,

said second screw extending downwardly through an oversize opening in said support element and being threaded into an internally-threaded portion of said tuning fork at least in the vicinity of said base.

31. The invention as claimed in claim 30, in which a spring is seated between said tuning fork and said support element, said spring being disposed to prevent excessive movement of said tuning fork upon striking of said one leg by said hammer means.

32. An electrical musical instrument, comprising:

a tuning fork having a base and a plurality of legs,

manually-operable hammer means to strike one leg of said tuning fork and set the same into vibration in a predetermined plane,

pickup means operatively associated with said fork to sense the vibration thereof,

a support element for said tuning fork,

a soft pad of resilient material seated between said support element and a portion of said base remote from the legs,

a screw inserted through an oversize opening in said support element and threaded into an internallythreaded opening which is formed in said tuning fork at least in the vicinity of said "base,

said screw being disposed in said plane of vibration and being generally perpendicular to said one leg.

33. The invention as claimed in claim 32, in which a second soft pad of resilient material is provided loosely between the remaining leg of said fork and said support element, said second pad being disposed to prevent substantial shifting of said fork in response to striking of said one leg by said hammer means.

34. The invention as claimed in claim 33, in which each of said soft pads is formed of felt.

35. An electrical musical instrument, whichcomprises:

an elongated vibratory tone generator having a base and at least one leg,

a support,

means to mount said tone generator in cantilevered relationship from said support,

said mounting means comprising first and second elongated fastener elements disposed in generally parallel relationship and connected to said support,

said elements extending through oversize openings in said tone generator in the region of said base thereof, said mounting means further comprising spring means to maintain said base of said tone generator in the extreme position permitted 'by said fastener elements, and

hammer means to strike said leg of said tone generator to set the same into vibration.

36. An electrical musical instrument, comprising:

an elongated vibratory tone generator having a highmass leg and a low-mass leg,

said tone generator also having a base region adjacent the connection between said high-mass and low-mass legs,

a support element,

first and second screws extended through oversize openings in said base region and threaded into said support element,

spring means disposed between said support element and said base region to maintain said base region in the extreme position permitted by the heads of said screws,

a soft vibration-damping element disposed between said base region and the head of at least one of said screws, hammer means to strike said low-mass leg to set said tone generator into vibration, and

pickup means to sense said vibration of said low-mass leg.

37. The invention as claimed in claim 36, in which said screw heads have generally frusto-conical undersurfaces, and in which said base region is-generally frustoconically counterbored around said openings to provide a self-centering function relative to said screw heads.

38. The invention as claimed in claim 36, in which said spring means comprises first and second helical compression springs disposed, respectively, around said screws and seated between said base region and said support element.

39. The invention as claimed in claim 38, in which said springs are countersunk into said base region of said tone generator.

References Cited UNITED STATES PATENTS 2,972,922 2/1961 Rhodes 84--1.l5

ARTHUR 'GAUSS, Primary Examiner.

D. D. FoRR'ER, Assistant Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 ,384 ,699 May 21 1968 Harold B. Rhodes It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

Column 9, line 16, "biase" should read bias Column 11, line 9, after "applying" insert means Signed and sealed this 27th day of January 1970.

(SEAL) Attest:

Edward M. Fletcher, Jr. WILLIAM E. SCHUYLER, JR.

Attesting Officer Commissioner of Patents 

3. AN ELECTRICAL MUSICAL INSTRUMENT, COMPPRISING: A TUNNING FORK HAVING A BASE AND A PLURALITY OF PRONGS, A SUPPORT, LEVER MEANS TO AMOUNT SAID BASE AND A PLURALITY OF PRONGS, SAID LEVER MEANS BEING ADJUSTABLE TO VARY THE PRECISE POSITION OF SAID BASE AND THUS OF SAID PRONGS, SAID LEVER MEANS BEING A THIRD-CLASS LEVER INCORPORATING SAID BASE AS A COMPONENT THEREOF, MECHANICAL-ELECTRICAL TRANDUCER MEANS, MEANS TO MOUNT SAID TRANSDUCER MEANS OPERABLY ADJACENT AT LEAST ONE OF SAID PRONGS TO SENSE THE VIBRATIONS THEREOF, THE RESPONSE GENERATED IN SAID TRANSDUCER MEANS BEING DETERMINED LARGELY BY THE ADJUSTED POSITION OF SAID LEVER MEANS, AND MEANS TO EXCITE AT LEAST SAID ONE PRONG TO SET THE SAME INTO VIBRATION. 